The present invention relates to an improved apparatus for manufacturing coated chain link fabric, especially chain link fabric of the type used in chain link fences and the like.
It is generally known to coat chain link fabric of the type having a plurality of intersecting wire-like members defining openings therebetween with a coating material to improve the wear characteristics and the appearance of the chain link fabric. In many instances, these coating materials consist of non-ferrous metallic coatings that are applied by passing the chain link fabric through a tank of the molten coating material and then cooling the fabric and coating material so as to harden the coating material on the fabric. For example, a chain link fabric made up of steel wire-like members may be coated with molten zinc, tin plate, or the like, using sequentially arranged coating and cooling tanks.
An important problem that occurs with the above-mentioned type of coating of chain link fabric relates to the uneven distribution of the coating material, which uneven coating is caused by the geometry of the intersections of the wire-like members in the fabric and by the different gravity effects on the molten coating during the manufacture. That is, the intersections tend to experience an excessive build up of the molten material and the underside of the wire-like members also tends to experience teat formation or excessive build up of the molten coating material.
The uneven coating of the chain link fabric prevents several basic disadvantages. First, the appearance of the finished product is substantially impaired by the uneven distribution and metal coating test formations. Also, the excess build up at the joints or intersections of the wire-like members of the fabric may freeze up the joints and prevent relative sliding movement of the wires at the joint, which results in an impairment of the operation of the chain link fabric during use. A still further disadvantage of the uneven coating relates to the relatively high cost for the coating material as compared to the basic wear-like members. Since the coating materials are usually much more expensive than the material being coated, and further since the utility of the coating as regards wear-resistance, weather-resistance, and the like is not substantially improved by the relatively thick excess build up of the coating material, the uneven coating results in excess expenditures for the coating material without a corresponding improvement in the end product.
It has been contemplated to attempt to overcome this uneven coating problem by striking the fabric with a wiper or flat piece that hits the wire and leaves a mark. With this so-called wiping method, the movement of the flat piece of metal is controlled by a motor. However, this method has the disadvantage that the wire of the chain link fabric is struck so as to leave a mark and the disadvantage that complicated motor and transmission mechanisms are needed to control the movement of the flat piece of metal that is to strike the fabric.
The present invention contemplates an improved apparatus for removing the excess coating material from the chain link fabric during the manufacture of the fabric. In one aspect, the present invention contemplates the method including the successive steps of passing coated chain link fabric over at least one sprocket member such that respective teeth of the sprocket member extend through openings in the fabric, and removing the fabric from the sprocket member such that the interengagement of the teeth and the fabric member upon removal of the teeth from the openings causes vibration of the fabric, which vibration causes excess coating material to fall from the fabric. A further aspect of the present invention involves the provision of notches along the length of the teeth on the sprocket member such that these notches cause a hitching and consequent vibration of the chain link fabric when the fabric is removed from the sprocket member. A further aspect of the present invention is the specific construction of the notches in the teeth of the sprocket member such that movement of the chain link fabric onto the teeth is relatively smooth while removal of the fabric from the teeth results in the hitching and vibration of the fabric to remove the excess coating material. A further aspect of the present invention is the provision of the sprocket members as one-piece cast members with a centrally disposed hub portion and radially outwardly extending teeth having a polygonal cross-sectional shape when viewed in the radial direction of the sprocket. The polygonal cross-sectional shape of the teeth can advantageously correspond to the polygonal cross-section of the openings in the chain link fabric being manufactured. A further constructional feature of the sprocket of the present invention is the arrangement of the outward ends of the teeth as pointed and tapering from the point to the polygonal cross-sectional shape so as to accommodate ready insertion of the teeth into the openings in the chain link fabric during the manufacturing operation.
The present invention also contemplates the arrangement of the sprockets intermediate a coating tank and a cooling tank with the chain link fabric being continuously guided through the coating tank over the sprockets and into the cooling tank and then onto a storage reel. This particular arrangement provides for a continuous manufacturing process whereby the removal of the excess coating material is done simply and in a continuous manner without interrupting the basic coating and cooling operations. The present invention also contemplates the arrangement of heating or flame mechanisms adjacent the sprocket members which heat the gang of sprockets so as to prevent annealing of the coating material to the sprocket structure. The present invention also contemplates the advantageous placement of the gang of sprockets such that the excess coating material removed during vibration of the fencing fabric by the sprockets is returned to the coating tank.
The above-discussed and other objects, features, and advantages of the present invention will become more apparent from the following description thereof, when taken in connection with the accompanying drawings.